Soil stabilizer composition and method of making from spent sulfite liquors



United States Patent 3,337 965 SOIL STABHLIZER COMPflSlTIQN AND METHOD 0F MAKIN G FROlt I SPENT SULFITE LIQUORS Shigeo Kiyooka and Jim Okahe, Iwakuni-shi, Japan, as-

signors to Sanyo Puip Company, Limited, Tokyo, Japan, a corporation of Japan No Drawing. Filed Apr. 21, 1965, Ser. No. 449,860 (Claims priority, application Japan, May 12, 1964, 39/26,559 5 Claims. (CI. 71-25) an... .n

ABSTRACT 0F THE DISCLOSURE This invention relates to soil stabilizer compositions. More particularly this invention relates to soil stabilizers of chrome-lignin type having remarkable soil stabilizing effect and obtained by treating spent liquor from sulfite pulp manufacture with chlorine in advance and adding thereto hexa-valent chromium salt alone or together with water-soluble salt of dior tri-valent metal.

There have been heretofore many methods proposed for stabilizing soil. it has been also known that spent liquor from sulfite pulp manufacture is made insoluble by adding bichromate salt and used for stabilizing soil in the name of so-called chrome-lignin process. In such a case, it has been also known that ion of metal such as iron, aluminum and copper increases the stabilizing effect. It has been also known that soil stabilization by the chrome-lignin process shows effect superior to that by soil cement method in the treatment for soil such as organovolcanic ash soils. However since in very one of these methods being used a large amount of expensive hexavalent chromium salt, for example sodium b-ichromate, they have drawback in the point of cost.

An object of the present invention is, accordingly, to provide soil stabilizer compositions which are not expensive but possess superior soil stabilizing effect.

After fully investigating the mechanism of spent liquor from sulfite pulp manufacture being turned insoluble by hexa-valent chromium salt, the inventors of the present invention found that the kind of spent liquor and various pretreatmeuts given to this spent liquor such as oxidation with air, oxidation with nitric acid, condensation, and chlorine treatment, have important relation with insolubilification and that the chlorine treatment among these is extremely effective for promoting insolubility.

Based upon these observations, the present inventors discovered that soil stabilizers which possess superior soil stabilizing effect and dispense with the use of expensive bichromate by about 20 to 30 percent, are produced by treating spent liquor from sulfite pulp manufacture with chlorine, and they further discovered that soil stabilizers of chrome-lignin type possessing excellent soil stabilizing effect are produced by incorporating bichromate and a water-soluble salt of dior tri-valent metal in chlorinated spent liquor from sulfite pulp manufacture.

According to the present invention, chlorine gas is introduced into spent liquor from sulfite pulp manufacture or concentrated liquor thereof at room temperature or under heating until the pH reaches 0.5 to 4.0. Therefore, a hexavalent chromium salt e.g. sodium bichromate is 3,387,965 Patented June 11, 1968 ice added directly to the resulting chlorine-treated liquor or to the substance obtained by drying (e.g. spray drying) the above-mentioned chlorine-treated liquor to produce soil stabilizers. Alternatively a water-soluble salt of dior tri-valent metal is mixed with the liquor obtained by the above-mentioned procedure. It is also possible to produce soil stabilizers by mixing a water soluble salt of dior tri-valent metal with sodium bichromate in advance and then adding this mixture directly to the above-mentioned chlorine-treated liquor or to the substance obtained by drying the above-mentioned chlorine-treated liquor. Alternatively, it is also possible to produce soil stabilizers by mixing a water-soluble salt of dior trivalent metal with the above-mentioned chlorine-treated liquor and thereafter sodium bichromate is added directly to the resulting mixed liquor or to the substance obtained by drying the mixed liquor.

Representative water soluble salts of diand tri-valent metals include metal chlorides such as CuCI MnCl and AlCl and metal sulfates such as CuSO MnSO FeSO and Al '(SO As spent liquor from sulfite pulp manufacture, those which are produced from broad-leaved trees (latifoliate trees) as the raw materials or those from needle-leaf trees (coniferous trees) are both useful but the latter is particularly suitable. It is preferable to use the fermented liquor from the latter.

It is possible to reduce the pH value in the reaction system with smaller amounts of chlorine when the temperature is elevated (7080 C.) during the chlorine treatment as compared to addition at room temperature. Generally speaking, the absorption amount of chlorine per unit of solid matter in spent liquor is preferably in the neighborhood of 6 percent. In this instance the chlorine content of lignin sulfonic acid is in the range of 1.7 to 2.0 percent. It is necessary to give attention so as not to add an excessive amount of chlorine since it causes oxidative degradation of lignin sulfonic acid which is harmful to the insolubilification in the next step. The optimum end point pH after chlorine treatment is 2.0 in the case of fermented spent liquor from needle-leaf trees. When spent liquor having low pH is used, it is preferable to neutralize until the pH reaches about 5 before chlorine treatment. Since the absorption of chlorine into spent liquor is carried out easily, there will be hardly any loss in such chlorine treatment.

As for the mixing method of the soil stabilizers of the present invention, these include the surfacelayer-sprinkling method, admixing method, grouting method and the like in the case of a solution, and simple mixing in the case of powder. Any of these methods is useful. The mixing amounts of water-soluble salt of dior tri-va-lent metal and chromium salts to the chlorination-modified lignin liquor can be varied according to the required strength of the soil and the allowable time (required) to be insoluble, and they are determined by the strength of gel and required gelation time shown in the following exemplary experiment.

EXEMPLARY EXPERIMENT 1) Definition of abbreviations of terms used in the experiment:

A Modified lignin liquor: Modified lignin liquor (containing 40 percent solid matter) obtained by introducing chlorine gas into spent liquor from sulfite pulp manufacture (pH 5) at room temperature until the pH reaches 2.

A Modified lignin liquor: Modified lignin liquor (containing 40 percent solid matter) obtained by introducing chlorine gas into fermented sulfite pulp spent liquor.

A Modified lignin powder: Modified lignin powder ob- 3 tained by spray-drying A down to 5 percent moisture. A Non-modified lignin liquor: Fermented (residue from) sulfite pulp spent liquor. (pH 5 and solid matter 40 percent.)

As is evident from the comparison of experimental results between. No. 1-1 or No. 1-2 and No. 1-11 in Table 1, the result of No. 1-11 is better, showing the superiority of the use of the modified lignin liquor. From the comparison B. 40 percent sodium bichromate solution. 5 of experimental results between No. 1-3 to No. 1-10 and C. Water-soluble salt of dior tri-valent metal: Chlorrd N 1 12 to Na 1 19 it i Seen that the i i of h was used as 40 Pelrcent Solutlon and sulfate and filtrate same amounts of C gives superior result in the combination were used 35 crystalwith A than in the combination with A Method dtlefmmmg gelatlofl time: The experimental results carried out for the saving A, B, water and C were mixed each in amounts pre- 10 of B by the addition of C is shown in Table 2.

TABLE 2 Mixing ratio (parts by weight) Required Gel Experiment N0. gelntion strength A pH of A B C Water time K-value (min) (kg/ch15) 2-1 A1100 2.0 10 100 050 7.3 2-2 A1 100 1 2. 20 100 12s 13. 0 2-3 A1 100 1 2. 0 30 100 23 10.1 24 A1 100 2. 0 10 100 247 11. 3 2-5 A1 100 2. 0 20 100 102 14. 2-0 A1 100 2. 0 30 100 55 10. 4 2-7 A1 100 2. 0 100 120 12.7 2-8 A1100 2.0 3 100 50 15.0 2-0 A1100 2.0 a 100 47 17.0 2-10, A1 100 2.0 25 3 100 17.0 2-11. A1100 2.0 10 3 100 150 11.8 2-1 A1100 2.0 15 3 100 105 14.7 2-13 A1100 2.0 20 FeSO4-7Hz0 3 100 07 15.7 2-14 A1100 2.0 25 Feso1-7H1o. a 100 as 10.1

1 Controlled by HCl. determined for the experiments. One hundred milliliters of (1) As is evident from the comparison of experimenthis mixed solution were charged in a glass vessel of 50 no tal results between No. 2-1 to No. 2-3, and No. 2-4 to mm. diameter and 60 mm. height and held in a 20 C. o No. 2-6, A even without being mixed with C, requires thermostat. The mixture commenced to gelate after a a gelation time shorter than A mixed with C. The gel while. The time required for the mixture to reach the state strength is also higher in the former. This shows that at which it did not fall even when the vessel was turned A enables to save B as compared to A1, upside down, was measured. (2) From the comparison of experimental results between No. 24 to No. 2-6 No. 2-7 to No 2-10 and or det rminin el stren th: (3) Methodf gg g No. 2-11 to No. 2-14, and comparing the points hav- A, B, w er an w re muted h in mo n s predetering the same values of required gelation time and gel mined for the experiments. One hundred milliliters of this strength, it is seen that the addition of C enables to save mixed solution were charged in a glass vessel of 50 mm. 40 B. Experimental results for the order of addition of B diameter and 60 mm. height and left at a temperature of or C to A are shown in Table 3. 20 C. for 24 hours for gelation. With use of an uncon- Note: In Experiment No. 3-1, B was added to A and fined compression apparatus, an iron cylinder of mm. then C was added thereupon. In Experiment No. 3-2, C diameter was inserted in the gelated mixture and the gel was added to A and then B was added thereupon. In pressures were calculated at 10 mm. penetration intervals. 45 Experiment No. 3-3, B was mixed with C at first and Table 1 indicates the experimental results of required A was added thereafter.

TABLE 3 Mixing ratio (by weight) Required Gel Experiment No. gelation strength A1 pH 01' A1 B 0 Water time K-value (min) (kg/emi 100 2.0 20 A1011 3 100 47 17.0 100 2.0 20 A1011 a 100 50 17.3 2.0 20 A1011 3 100 40 17.5

gelation time and gel strength obtained by adding various amounts of C to a definite amount of B.

TABLE 1 Mixing ratio (by weight) Required Gel Experiment No. gelation strength A; A1 pH oi B 0 Water time K-value A1 or A4 (min) (kgn/cmfi) 5.0 20 100 720 0.5 1 2. 0 20 100 210 12.1 1 2. 0 20 3 100 12a 13. 0 1 2. 0 20 3 100 133 14.1 1 2. 0 20 3 100 100 15. a 2.0 20 11111011.". 3 100 25 10.0 2.0 20 A11(s01).1-1sH1o 3 100 13.0 2.0 20 Feso1-7r-I1o a 100 129 15.1 2.0 20 Mns01-5H1O 3 100 s7 15.0 2.0 20 Al(NOa)1-9II1O.-. a 100 130 14.0 2.0 20 0 100 102 14.5 2.0 20 3 100 47 17.0 2.0 20 a 100 00 10.2 2.0 20 3 100 8 10.0 2.0 20 M11011 a 100 45 10.3 2.0 20 A1g(s04)3-18H20 3 100 50 10.1 2.0 20 Feso1-7H1o. 3 100 97 15.7 2. 0 20 MnSO4-5H O 3 100 40 20. 0 2.0 20 A1(N01)1-0H1 a 100 as 15.11

1 Controlled by H01.

As is evident from Table 3, the order of addition of B or C to A does not exert much influence upon the soil stabilizing eiiect.

Experimental results relating to the influence of the kinds of modified lignin are shown in Table 4.

6 Example 3 To 100 parts by weight of modified lignin liquor (containing 40 percent solid matter) obtained by blowing chlorine gas into spent liquor from sulfite pulp manufac- 1 Controlled by HCl.

(1) From the comparison A with A in Table 4, A from the fermented liquor which has a smaller content of sugar gives a somewhat better result.

(2) The comparison of A with A shows that there is hardly any difierence between these two.

Note: Since the solid matter in A in Experimental No. 4-3, is 95 percent, A and water in No. 4-3 are made into 42 parts and 158 parts, respectively so as to set the experimental condition at the same with that of Experiment No. 4-1 and No. 4-2.

The following examples are given to illustrate the present invention without limiting its scope.

The sulfite spent liquor, which was employed in the following examples, is that from Japanese red pine (Pinus densiflom) pulp manufacture. However, similar results could be obtained in other cases as compared with the Japanese red pine.

Example 1 To 100 parts by weight of modified lignin liquor (containing 40 percent solid matter) obtained by passing chlorine gas into spent sulfite liquor at 70 C. until the pH reaches to 2, were mixed 20 parts by weight of 40 percent sodium bichromate solution, and 100 parts by weight of water to produce a soil stabilizer.

The resulting soil stabilizer was mixed with loam type soil (containing 36 percent water) in a proportion of 20 percent by weight. The mixture was shaped into a cylindrical form (20 mm. diameter and 50 mm. height) and cured at a temperature of C. for 7 days in a room. The unconfined compression strength of this material was 5.9 kg./cm.

For control, an unmodified conventional sulfite spent liquor (pH 2 and containing 40 percent solid matter) was employed as above, and the unconfined compression strength of this control sample was 3.8 kg./om.

Example 2 To 100 parts by weight of modified lignin liquor (containing 40 percent solid matter) obtained by blowing chlorine gas into spent liquor of sulfite pulp manufacture at room temperature until the pH goes from 5 to 2, were mixed parts by weight of 40 percent sodium bichromate solution, 3 parts by weight of 40 percent aqueous solution of AlCl and 100 parts by weight of water to produce a soil stabilizer.

The resulting soil stabilizer was mixed with loam type soil (containing 36 percent water) in a proportion of 20 percent by weight. The mixture was shaped into a cylindrical dorm (20 mm. diameter and 50 mm. height) and cured at a temperature of 15 C. for 7 days in a room. The unconfined compression strength of this material was 6.4 kg./cm.

ture at room temperature until the pH goes from 5 to 2, were added 20 parts by weight of 40 percent aqueous solution of sodium bichromate, 3 parts by weight of 40 percent aqueous solution of FeSO -7H O and parts by weight of water to produce a soil stabilizer.

The resulting soil stabilizer was mixed with loam type soil as in Example 1 and its unconfined compression strength was measured whereby the value of 6.0 k-g./cm. was obtained.

What we claim is:

1. A process for preparing a soil stabilizer which comprises chlorinatin-g a sulfite pulp waste liquor containing lignosulfonic acid until said sulfite pulp waste liquor has a pH of 0.5-4.0 and said lignosulfonic acid has 1.7- 2.0% by weight of combined chlorine to modify the sulfite pulp waste liquor and adding to the thusly modified sulfite pulp waste liquor 0.04 to 0.12 part of a compound of hexavalent chromium by weight per part of sulfite pulp waste liquor.

2. A process according to claim 1 wherein the compound of hexavalent chromium is sodium bichromate, the process further comprising adding to the modified sulfite pulp waste liquor a water soluble metallic salt selected from the group consisting of divalent and trivalent metal salts of iron, aluminum, manganese and copper.

3. A process according to claim 1 wherein the sulfite pulp waste liquor is a fermentation waste liquor.

4. A soil stabilizer comprising a modified sulfite pulp lignin mixture consisting essentially of a chlorinated lignosulfonic acid, 0.04 to 0.12 part by weight of a compound of hexavalent chromium per part of modified sulfite pulp liquor per part of modified sulfite pulp lignin.

5. A soil stabilizer according to claim 4 wherein the compound of hexavalent chromium is sodium bichromate and the stabilizer further comprises a water soluble metallic salt selected from the group consisting of divalent and trivalent metal salts of iron, aluminum, manganese and copper.

References Cited Kirk and Othmer: Encyclopedia of Chemical Technology, vol. 9, 1952, p. 333, Interscience, New York.

S. LEON BASHORE, Acting Primary Examiner.

DONALL H. SYLVESTER, Examiner.

R. BAJEFSKY, Assistant Examiner. 

